Sensitive relay



Feb. 2, 1954 LAMB r 2,668,208

SENSITIVE RELAY Filed Sept. 15, 1951 2 Sheets-Sheet l ANTHONY/f. LAMBAND ELMER 6. DEMOTT INVENTORS ATTO EYS 1954 A. H. LAMB ETAL 2,668,208

SENSITIVE RELAY Filed p 1 2 Sheets-Sheet 2 u I I; 5:: 8, Y a 74 75 T I/I I I I I l :2 Wi mm! I.

V I I j I, 6'0 1 36 I 2 a I ANTHONY H. LAMB AND 40 37 40 ELMER 6. DEM077 INVENTORS #LIO v BY 2a Arm 5 Patented Feb. 2, 1954 SENSITIVE RELAYAnthony H. Lamb, Hillside, and Elmer G. De Mott, Chatham, N. .L,assignors to Weston Electrical Instrument Corporation, Newark, N. J acorporation of' New Jersey ApplicationSeptember 15, 1951, SerialNo.246,726

10 Claims. (01. 200-110) This, invention relates to sensitive relays andmore particularly to sensitive relays of the magnetic contact-type.

Relays of the type contemplated by this invention include a movablecontact arm carrying a, contact in the form of a magnetic. rider forcooperation with a stationary contact constituted by a. small magnet.When the relay arm moves toward, the stationary contact the rider comesinto the. field ofv magnetic influence of the magnet and is attractedthereto to provide a good, firm contact closure. In general, themagnetic contact so established requires some mechanical means forseparating the rider from the magnet a the movable coil of the relay isincapable of generating sufficient torque for this purpose.

In prior relays of this type the stationary contact. comprises a smallpermanent magnet suitably mounted to provide electrical isolationbetween the magnet and other parts of therelay. While such design hasproven. satisfactory for many applications, the manufacture of thepermanent magnet and the assembly thereof in a relay is rather costlyand does not lend itself to the production of inexpensive relays. Thepresent invention is directed to a relay design emplaying the desirablefeatures of a magneticcontact relay but, which is of simple-constructionand which is adapted for the production of low cost relays.Specifically, the stationary contact com.- prises a soft-iron memberdisposed in the vicinity of the. relay magnet such member beingadjustably fastened to the relay base. By reason of its position. in themagnetic field of the relay magnet such member becomes, magneticat itsing, a. ready means for altering the deflection characteristics of therelay coil.

A relay made in accordance with this invention includes numerous otherfeatures directed toward the Provision of a small, low cost, highquality relay. The individual relay components are all supported from acommon base made of insulatin material, and are secured in position bynovelv means that also serve as terminals by which the relay canv beconnected into an external circuit. The relay case itself is. of simpleconstruction and consists of. two, parts, a. base carrying the relaycomponents, and acover car- III rying a simple mechanical arrangementfor separating the relay contacts.

An object of this invention is the provision of a permanent-magnet,movable-coil relay of the magnetic contact type wherein the relaycontacts are actually made of a low reluctance magnetic material suchassoft-iron.

An object of this invention is the provision of a permanent-magnet,movable-coil relay of the magnetic contact type wherein the stationarycontacts comprise adjustable soft-iron members having portions lying inthe magnetic flux field of the primary magnet of the relay.

An object of this invention is the provision of a sensitive relaycomprising a permanent magnet core supported between the legs of anonmagnetic U-shaped bracket, a movable coil pivotally mounted betweenthe legs of the said bracket and rotatable about the core, soft-ironmembers disposed on opposite sides of the core and spaced from themovable coil, a pointer or contact arm carriedby the coil, and amagnetic material rider secured to the end of the pointer, said rideradapted to contact each of the said soft-iron members upon rotation ofthe movable coil.

An object of this invention is the provision. of a sensitive relaycomprisin a base of insulating material, a non-magnetic U-shaped bracketsecured in upright position to said base, a cylindrical permanent magnetcore secured between the legs of the U-shaped bracket, a movable coilpivotally mounted between the legs of the U-shaped bracket and rotatableabout the core, a pair of soft-iron members secured to the base anddisposed on opposite sides of the said core, each of said members beingspaced from the coil and including an elongated end, a contact armcarried by the coil, a magnetic material rider carried by the end of thecontact arm, a cover member cooperating with the base to form a closedcase, and a finger-operable mechanism carried by the cover and adaptedupon operation to contact the said contact arm.

These and other objects and advantages will be apparent from thefollowing description when taken with the accompanying drawings. Thedrawings are for purposes of illustration and are not to be construed asdefinin the scope or limits of the invention, reference being had forthe latter purpose to the appended claims.

In the drawings wherein like reference characters denote like parts inthe several views:

Figure l is an exploded view, in isometric,

arm 28.

.tified by the numeral 3!.

showing the major components of a relay made in accordance with thisinvention;

Figure 2 is a cross sectional view taken along the line A-A of the baseshown in Figure 1;

Figure 3 is a cross-sectional view taken along the line B-B ofthemcunting bracket shown in Figure 1;

Figure 4 is a side view showing the mounting bracket and permanentmagnet core mounted upon the relay base;

Figure 5 is an isometric view showing the mounting bracket and the twosoft-iron contact members mounted on the relay base;

Figure 5 is a cross-sectional view taken along the line C-C of Figure 5and showing how one of the screws employed to secure the soft-ironcontact members to the base also serves as a connection terminal;

Figure '7 is an isometric view of the relay cover that carries thefinger-operable contact-resetting mechanism;

Figure 8 is a front view of the relay with the cover in place, the coverbeing shown in crosssection and the resetting mechanism being omittedfor purposes of clarity; and

Figures 9 and 10 are fragmentary illustrations intended to facilitate anunderstanding of the operation of the resetting mechanism.

Referring now to Figure 1, the relay base l0, made of asuitableinsulating material such as a plastic, is a unitary memberprovided with a shoulder H and raised portion 52. The base is providedwith the threaded inserts l3, l4, l5 and IS, a pin-type terminal ii, ahole H3, and a recessed hole Hi, the purpose of which will befitted intosuitable holes provided for this purpose.

, The relay mechanism comprises a U-shaped bracket 29 having atransversely-magnetized, permanent magnet core 2! secured thereto. Itmay here be stated the bracket 29 is made of a non-magnetic material,such as brass, and forms no part of the magnetic flux circuit. A wirewound movable coil 23 is pivotally supported between the legs of theU-shaped bracket, such coil being provided with conventional pivotsrotatable within jewel screws, one such jewel screw 24 being visible inthe drawing. As is well known in this art, current is conducted to themovable coil by a set of spiral springs 25, 25, each spring having aninner end secured to the adjacent pivot base and the outer end securedto an abutment. In the present case, the upper spring 25 is secured tothe abutment 2'! which is rotatable in response to rotation of theconventional zero-corrector The abutment 21 and arm 28 are grounded tothe bracket 25]. In such case, the lower spring 26 must be electricallyinsulated from the bracket. This is accomplished by insulating the lowerabutment 39 from the bracket 20 as shown more clearly in Figure 3 whichis a cross sectional view taken along the line BB of the lower leg ofthe bracket, shown in Figure 1. In Figure 3, the lower leg of thebracket is iden- The abutment 3E3 is secured to the leg 3! by aninternally-threaded rivet 32 and the abutment is insulated from thebracket leg by a combination of the insulator bushing 33 and insulatorwasher 34, as shown. The outer end of the lower spring 26 (Figure 1) issoldered to the inner end 35 of the abutment 4 30 (Figure 3). It is herepointed out that the recessed hole is, in the relay base It is designedto accommodate the head of the rivet 32 and the insulating washer 34when the relay mechanism is secured to the relay base, as will beexplained with reference to Figure 4, below.

With further reference to Figure 1, the relay mechanism includes apointer, or arm, 36 that is secured to the movable coil 23 said armcarrying a soft-iron rider 3'? on its free end. As shown, the mechanismis complete in itself and can be assembled and adjusted outside of therelay case. All parts of the mechanism are readily visible andaccessible thereby promoting reduced manufacturing costs.

The stationary contacts of the relay comprise the soft-iron members 40,40' having reverselybent base sections 4!, 4!, respectively, each basesection provided with a air of holes. The holes 42, 43, in the member 40are spaced to aline with the threaded inserts I5, It in the relay base10 and such member 58 can be secured to the base by a threaded post 44and a screw 55, as will be described in detail hereinbelow withreference to Figures 5 and 6. The other soft-iron member 4| is likewisemountable on the base it by the post 44 and screw 45'.

Reference is now made to Figure 4 which is a side view showing the relaymechanism mounted on the relay base; the movable coil, springs, etc.being omitted for purposes of clarity. In this view the spacer member 22is shown between the magnet and the bracket wall. The use of suchspecific spacer member, which can be soldered or welded to both themagnet and the bracket, is optional. The magnet can be spaced from thebracket wall by forming a longitudinal detent in the bracket. TheU-shaped bracket 26 is secured to the base It by a screw '50 and athreaded terminal 5| passing through the holes l8, 59 shown in Figure 1.The screw 58 is threaded into the internally-threaded rivet 32 (seeFigure 3) and the terminal 51 is threaded into a threaded hole 52 in thelower leg of the bracket (see Figure 1). Therefore, the lower leg of thebracket rests flat upon the surface of the base and the mechanism issecured firmly thereto. By soldering a lead 53 between the pin terminalI! and the lower abutment 38, it will be apparent the movable coil ofthe relay can be connected to an external circuit by means of the pinsl1 and 5| (since the lower coil spring is connected the abutment 3i andthe upper coil spring is grounded to the bracket 20). It is also quiteclear that the terminal l! and the lead 53 can be omitted if the screwso be replaced by a threaded terminal pin similar to the pin 5 l. Suchthreaded terminal pin will serve the dual purpose of securing thebracket to the base and as a means for connecting the ungrounded side ofthe movable coil to an external electrical circuit.

Reference is now made to Figure 5. The relay mechanism is shown mountedon the base 10, as just explained; the movable coil, springs, abutments,etc., being omitted. However, the relay movable arm 36 and the ironrider 3? are shown in proper position relative to the stationary contactmembers iii, 4!! now shown secured to the base Iii. As shown in Figure6, which is a cross sectional view taken along the line C--C of Figure5, the lower, threaded end of the post 45' is threaded into the insertl3 and the screw 45 is threaded into the insert I i it being noted thatthe reduced-diameter pin section 55 of the screw extends through theinsert to provide a terminal for connecting- .the' softairon. member;4.0:! to. an 6190: triiialfcircuit; The holes: 42', 453:; (see. Figure;11):. in the. base section 41. ofizthesoitr-ironimember Mfr-are.enlarged; or clearance holes whereby the position ofithemember can be.adjusted relar tive to the magnetic core 21:. The. other soft,"- rron.member 43; is. secured, similarly, to. the base H] :andll-i'esdiai-netricall-y opposite: to the member 401' with respect. to: thecore-'25. In the illustrated construction the screw has; a. reduceddiameter pin section passing through the insert. 1:4.to. serve as anexternal connection terminal. while/the threaded. end of the post M1terminates within the. threaded insert I31. To further reduce the costof.- the relaya. somewhat reverse arrangementais. employed.Specifically, the post: 4.4," in: cludes an integral pin sectionextending; from the. externally-threaded. end,v such, pin sectionpassins through the insert I13: to, serve, as the ex: ternak connection.terminal. screw: 55.- and insert. 84; can be omit-t In;- the event. amore. positive arran ement. desired to prevent possible: rotation. f thmember is abo t the, axis. oi the. post. 44; the relay; base. can; beprovided. an. integral recess having one or more; side walls abuttingagainst the edges of the base section of the. member at.

It is; to be noted. the: soft-iron members t, it are. spaced; from themagnet core. Essentially,

the coreis a free. magnet in space and the men J Ways, namely, by thethickness and size. of the.

members 48,, it, by the spacing of one or both of these. members withvrespect to. the core, and by appropriately shaping that portion of thesemembers lying within the ran e. of, rotation of the movable coil. In.the. latter case, for example, the 4..

body of one or both of the. soft-iron. members 40, 40 may be arcuateinstead of flat asshown. Since the members, 40., 4t" lie within themagnetic flux field, lines of flux, will. emanate from the edges thereofand such flux linesserve. to attract the soft-iron rider BIcarried bythe relay pointer. 35.. In a rel y constructed. as shown, the. magneticattraction holding. the rider't'o. the edge or the stationary soft-ironmember is. s'uiiicient tov prevent separation oi the. contactsjeven whenthe relay is suh,iepcted to severe, mechanical; shock.

It. will be apparent from the. description. thus far presented that the.individual parts ofthe relay are of. simple. construction, a e e sily.as,-' sembled in proper relative. position, that the parts carried bythe relay base constitute. a complete, operative relay with theexception of a suitable mechanicalmeans tor separating thev iron riderfrom either [of the stationary contacts.

The resetting mechanism of our relay iscarried y the relay Coven. asshown in F gu 7- The cover 6c is made of a transparent plastic and hasintegral ears GI extending irom'opposite sides, said ears serving as. ameans for mounting. the complete relay on panel or other apparatus. The.top of the cover carricsa rotatable zero adluster screw 62-..05 more orlessconventional censtructi-on..- Rotation of, the screw c2, impartsanoscillatory movement. tgthe, pin; .63, which engages a suitable. arm.extending. from. the. ten of he. relay Insuch s n the.

6 mechanism as willhe explained hcreinhelow with referencezt'o Figures;Thetop surfaceot}, the cover is also provided with 100. 64 0 a ommo datesuitable screws. for fastening; the cover in. position over the; relaybase. The contact13esetting mechanism comprises the flat rod or platefiihaving an. integral tip 6.5 of rectangular cross, section, whichextends througha rectangular slot in the. cover wall. Surrounding the;tip BB -is-a helical compression, spring 61; having one endin1 contactwith the inner wall of the cover and; the; other end abutting againstthe resulting shoulder of the plate 2'55, as shown. A suitablewasher 68secured to the enctcf thev tip that lies cut side of the cover from.which; it isapparent the spring 61 applies a mechanical bias to theplate. 5.5: direction such that the washer fit'normallyg abuts againstthe cover 60. In such,norma1-pQsi-. tion of the resettingrmechanism asubstantial, portion of the end 63 of? the plate; 65 extends, ou -lwardi ofthe cover through a, suitable rectangus. lar slot in the coverside wall. Finger pressure applied to the end 6.9 of the plate willcausethe plate 55 to move along the axis-oi the spring 61;

' asthe said-spring is compressed. Release of such pressure. permits thespring to returnthe plate. to the position shown in Figure Since the end59 and tip 55 arev of rectangular cross section. each operable with'anappropriate rectangular slot in the side wall of the cover,; a. smooth.monoplanar movement of the plate 5.5 is assured. shown in the drawing,the upper side of; the plate 5.5; may be provided with a recess lit inthe event; the upper side edge of the plate 6.5: is designed to,

contact the-inner surface ofthe covertop, In;

such case only the edges "H and; ll of the plate will rub against thecover top during operation or the. reset mechanism, thereby: red cingthe. iii-iction between: the plate and cover top. Moreime portantly; theplate 65 is; provided withanother recess 13 resulting in; thedownwardly-depending edges 14', 1.5. When the cover '69, is secured inposition. on. the relay base the resetting; mechanism will occupy a.position such that the. relay: movable. arm operates within the recessl3: and is; subject to contact by the edge M.- or 15 for re settingpurposes as will. bedescribed with reference: to Eisureseand 1c. YFigure 8 illustrates the relay with the cover in place. Forpiirposes ofclarity the, cover 5?), is shown in crossv section and the spiralsprings andabutments of the mechanism have been omitted. It willbenoted: open. end oi the cover B l-rests. upon the lip H of: the relaybase i-J and the cover iS'l secured in; p sition by the screws-8threaded; into the upper ends of the posts. 44; 6.4. The-tip S3. of: thezero adjuster mechanism extendsthrough a slot in the zero-adjuster arm28- where bythe normal, or zero current, position, of. the movable coil23 can be altered by rotation-0t the screw 6.2.

"Reference is new to. Figures 9 and 10 which are fragmentary 'viewstaken from the front; of theI instrument. In- Figure 9; the contactresetting mechanism. is shown in its normal position, that. is, thewasher 5t abuts-against. the cover side wall. The movable arm 35 of,therel-ay mechanism rotates about the axis a---c (defined by the pivotsof the movable coil) and the plate 3.5 is so positioned that thedownwardly-depending edges M, intersect the plane in which the uppersection of the a rotates. Consequently, when the plate.- .s inits normalposition tl e. extent of. rotation of the arm. 3.5182113}?- i'ted; bythe edges 14, is. Under such condition.

the iron rider 3'! is free to contact the soft-iron member 49 but notthe member 60'. Now, if the plate 65 be moved inwardly of the cover 50the edge 14 will move the arm 36 causing a separation of the rider 3'!and the member 40. The extent of linear movement of the plate 65 is suchthat the rider 3'! is moved out of the magnetic field of influence ofthe member 40 whereby the position of the arm 36 will be controlled bythe current flowing through the movable coil of the relay upon asubsequent return of the plate 65 to its normal position.

The innermost position of the plate 65 is shown in Figure 10. In suchposition of the plate the edge 14 prevents contact of the rider 3! withthe stationary contact 40 while permitting contact between the rider andthe contact 40. Upon closure of the contacts constituted by the riderand the member 40' contact separation is accomplished when the plate 65is returned to its normal position under the action of the spring 61, asshown in Figure 9.

It will now be apparent the plate 65 serves two purposes, namely, tocondition the relay so that the iron rider can contact only one or theother of the stationary contacts and to separate the contacts so madeupon selected movement of the reset mechanism. A relay of thisconstruction is adapted for use in on-ofi control systems wherein aclosure of one set of contacts results in, say, an energization of aload device after which such contacts are opened by manual orelectromagnetic movement of the resetting plate. Upon such energizationof the load device the relay is conditioned for 'a closure of the otherset of contacts that results in a de-energization of the load device.

Having now described our invention the many features thereof areapparent. The individual parts are of simple construction and easy to assemble and replace. The stationary contacts are made of a low reluctancemagnetic material positioned and shaped to control the magnitude anddistribution of the magnetic fiux field within which the movable coiloperates. These same contacts become magnetized at their cont-actmakingends to provide a good magnetic contact type relay. Further, thesecontacts are secured to the base of the relay in such fashion that theirposition relative to the permanent magnet coil may be adjusted to alterthe deflection characteristics of the relay. At the same time the meanssecuring the stationary contacts to the base serve as the means forconnecting them into an external electrical circuit thereby eliminatingseparate connection straps, terminals, etc. While the pin typeconnection terminals extending from the lower surface of the base can beused as soldering terminals for connecting the relay into a network suchpin terminals, preferably, are designed to provide a plug-in type relay.In the latter case, the pin terminals establish friction contact withsuitable, hollow terminals carried by a socket, the arrangement beingsimilar to the conventional radio tube-socket combination. 'Stillfurther, a simple, inexpensive reset mechanism is provided which notonly separates the relay contacts but also conditions the relay properlyfor the next operating cycle. These features are attained in a relay ofexceptionally small size and without sacrifice of any desired operatingcharacteristics found in conventional relays of this class.

While we have illustrated and described a simple D.-C. version of therelay the invention is not limited thereto. The relay can be used on 8A.-C. currents by incorporating therein a suitable rectifier comprisinga series of asymmetricallyconducting discs. Such discs, as well asresistors, can be disposed within a suitable recess provided in therelay base, particularly in the raised portion I2 as shown in Figure 1.

Numerous changes and modifications of the individual parts and theircooperating assembly will present themselves to those skilled in thisart without departing from the spirit and scope of the invention as setforth in the following claims.

We claim:

1. In a relay of the type including a pair of stationary contacts and acooperating movable contact for controlling an electrical circuit, thecombination of a base of insulating material, a U-shaped bracket securedto the base, a permanent magnet core secured to the bracket and disposedbetween the legs of the bracket, a movable coil pivotally supported bythe bracket and rotatable about said magnet core, a movable arm securedto the movable coil and having a free end normally extending beyond therange of magnetic influence of the magnet core, a rider of magneticmaterial carried by the free end of said movable arm, and soft-ironmembers secured to the base and electrically insulated from each otherand the bracket, said members being disposed on opposite sides of andspaced from the movable coil and magnetic core and including portionsdisposed in the field of travel of the said rider, the said rider andsoft-iron members constituting the contacts for controlling theelectrical air-- cuit.

The invention as recited in claim 1, wherein the said soft-iron memberscomprise a base portion secured to the relay base, an offset centralportion spaced from the movable coil and a pro- J'ecting end sectionlying in the path of travel of the rider.

3. The invention as recited in claim 1 wherein the soft-iron members areadjustably secured to the base.

4. The invention as recited in claim 1 wherein the said soft-ironmembers are secured to the base by a threaded member having a pinsection proiecting from the relay base.

5. A relay comprising a base of insulating material; a U-shaped bracketof non-magnetic material disposed in upright position on the base; athreaded, pin type terminal member passing through a hole in the baseand into a threaded hole in a leg of the bracket, a movable coilcarrying a pointer and pivotally supported between the legs of thebracket; a rider of magnetic material carried on the end of the pointer;a trans versely-magnetized, substantially-cylindrical permanent magnetcore secured to the base of the bracket and disposed within the movablecoil: a soft-iron member having an end section disposed in the path oftravel of the said rider, a mid-section spaced from the movable coil andmagnetic core, and a base section adapted for flush contact with therelay base; a pair of holes in the base section of the soft-iron member;internally threaded inserts in the relay base said inserts alined withthe holes in the base or the soft iron member; and fastening memberspassing through the holes in the base section of the soft-iron memberand into the inserts.

6. The invention as recited in claim 5 wherein one of the said fasteningmembers includes an integral, reduced diameter extension passing throughthe associated insert.

7. The invention as recited in claim 5 wherein one of the said fasteningmembers is a post extending upwardly in spaced relation to the saidsoft-iron member.

8. The invention as recited in claim 7 in combination with a coverhaving an open end in contact with the relay base; a hole in the cover;and a screw member passing through the cover hole and threaded into anend of the post.

9. The invention as recited in claim in combination with a cover; meansremovably securing the cover to the relay base; and anexternally-operable reset rod supported by the cover for linear movementwithin the cover, said rod adapted to contact the said pointer upon apredetermined movement of the rod.

10. A sensitive relay comprising a base of insulating material providedwith a shoulder, a pivoted movable coil rotatable about a substantiallycylindrical, transversely magnetized permanent magnet; a U-shapedbracket supporting the movable coil and magnet in operative position;means securing a leg of the bracket to the base whereby the bracketextends upwardly from the base; a pointer secured to the movable coiland carrying a soft-iron rider; a pair of softiron members disposed onopposite sides of the permanent magnet and spaced from the movable coiland magnet, each said member including a section adapted for contact bythe said rider; means securing the said soft-iron members to the relaybase said means including a. pair of posts extending upwardly from therelay base; a cover having an open end disposed on the shoulder of therelay base and including a pair of holes alined with the said posts;screws passing through the cover holes and into the said posts; atransversely-movable reset rod having ends extending through aperturesin opposed side walls of the cover; a spring biasing the said reset rodto a normal position; a recess in the wall of the reset rod said recessbeing defined by side walls adapted to engage the said pointer toseparate the iron rider from either of the said soft-iron members.

ANTHONY H. LAMB.

ELMER G. DE MOTT.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 989,420 Reichel Apr. 11, 1911 1,958,713 Reyman May 15, 19342,014,387 Lamb Sept. 17, 1935 2,102,409 Faus Dec. 1 1, 1937 2,203,727Herbst June 11, 1940 2,262,504 Lamb Nov. 11, 1941 2,565,312 Lamb Aug.21, 1951 FOREIGN PATENTS Number Country Date 362,116 Great Britain Dec.3, 1931

